Why is my battery dead?

[Humpy D]

I have an 18 month old Ford Focus which has a heated windscreen.

On Tuesday I got back to the car to find it covered in snow, got in to start it and all was fine. The heated windscreen switched on but then the windscreen cracked along the bottom started from an old (repaired) stone chip.

No worries (so I thought) but when I tried to start the car on Friday (after having sat idle for 2 days) it was dead. Jump started it on Saturday without any problems but then this morning it is dead again.

I've checked that nothing has been left on (interior light, headlights, etc) but can't see anything. Just wondering whether the crack in the windscreen is shorting something out and draining the battery.

Any ideas?

[jbi]

Crap battery struggling in the cold?... get a garage to test it and your alternator.

Edited by jbi on Sunday 5th December 13:15

[EDLT]

If its a two-year battery then maybe the cold has killed it early.

[redvictor]

jbi said:

Crap battery struggling in the cold?

Modern batteries require constant everyday running. Anytime you leave it in severe weather for a while makes it prone to failure.
It's all to do with cheap..

[jagracer]

Check all the terminals are tight or they may need leaning up, if that doesn't help get the battery checked.

[Animala]

I bet you found it rather shocking when the battery wouldn't work

[Parrot of Doom]

The crack has nothing to do with the battery, since the heated windscreen won't come on without the key in the correct position.

Quite simply you haven't been driving it enough, and the battery is flat.

[Humpy D]

Parrot, it just seemed a coincidence. I'd be surprised if it was because of not using it enough though; it was only 2 days!! The car was fine earlier in the year when I left it at the airport for 2 weeks!

[Puddenchucker]

Humpy D said:

On Tuesday I got back to the car to find it covered in snow, got in to start it and all was fine....

...No worries (so I thought) but when I tried to start the car on Friday (after having sat idle for 2 days) it was dead. Jump started it on Saturday without any problems but then this morning it is dead again.

Between starting it on Tuesday and trying to start it on Friday, how far did you drive?

[jagracer]

Puddenchucker said:

Humpy D said:

On Tuesday I got back to the car to find it covered in snow, got in to start it and all was fine....

...No worries (so I thought) but when I tried to start the car on Friday (after having sat idle for 2 days) it was dead. Jump started it on Saturday without any problems but then this morning it is dead again.

Between starting it on Tuesday and trying to start it on Friday, how far did you drive?

Providing the battery is OK it should last more than two days even in the cold we have had this week. It's either a shagged battery or some fault with connections or charging.

[paintman]

Humpy D said:

Parrot, it just seemed a coincidence. I'd be surprised if it was because of not using it enough though; it was only 2 days!! The car was fine earlier in the year when I left it at the airport for 2 weeks!

The cold weather really sorts out old & dying batteries.

If you're only doing short journeys & using lots of electrics - HRW, HFS,lights, heater blower - which is normal at this time of year then your alternator is really struggling & won't put a lot back into the battery. So the charge is dropping. Standard fit (read as 'minimum requirement')alternators are intended to power the car electrics & keep the battery topped up. They aren't intended to keep recharging flat batteries & if you do then you will shorten the alterntors life. If you have lots of extra electrical goodies fitted then consider a bigger (higher output) alternator.

If your battery has run down & it needed a boost start, fully recharge with a battery charger then see if it holds the charge.

Be careful jump starting as doing it wrong can cause expensive damage to the electronics fitted to modern cars.

If the level in your battery has dropped & the tops of any of the plates are exposed then it will lose its charge even faster (assumes a non sealed for life battery)

Edited by paintman on Sunday 5th December 15:39